Meritocracy a myth? A multilevel perspective of how social equality accumulates through work

Work plays a crucial role in rising social inequalities, which refer to unequal opportunities and rewards for different social groups. Whereas the conventional view of workplaces as meritocracies suggests that work is a conduit for social equality, we unveil the ways in which workplaces contribute to the accumulation of social inequality. In our Cumulative Social Inequality in Workplaces (CSI-W) model, we outline how initial differences in opportunities and rewards shape performance and/or subsequent opportunities and rewards, such that those who receive more initial opportunities and rewards tend to receive even more over time. These cumulative social inequality dynamics take place via nine different mechanisms spanning four different levels (individual, dyadic, network, organizational). The CSI-W indicates that the mechanisms interact, such that the social inequality dynamics in workplaces tend to (a) exacerbate social inequalities over time, (b) legitimate social inequalities over time, and (c) manifest themselves through everyday occurrences and behaviors

Joint Stiffness Compensation for Application in the EXTEND Hand Orthosis

This paper presents a passive hand orthosis, called EXTEND, that can be used during activities of daily living. In the design a negative stiffness spring mechanism is incorporated to overcome the high finger joint stiffness of stroke patients with hypertonia. The passive mechanism can be easily tuned by the user to compensate a linear joint stiffness of 0.15 to 0.33 Nm/rad for each finger independently. A prototype was tested with four patients showing an increased functional ability of the hand during several tasks. With the orthosis, patients were better able to pick up mid-sized objects (5-7.5cm diameter) of different shapes.</p

An explorative, cross-sectional study into abnormal muscular coupling during reach in chronic stroke patients

Background\ud In many stroke patients arm function is limited, which can be related to an abnormal coupling between shoulder and elbow joints. The extent to which this can be translated to activities of daily life (ADL), in terms of muscle activation during ADL-like movements, is rather unknown. Therefore, the present study examined the occurrence of abnormal coupling on functional, ADL-like reaching movements of chronic stroke patients by comparison with healthy persons.\ud \u

Vortices in vibrated granular rods

We report the experimental observation of novel vortex patterns in vertically vibrated granular rods. Above a critical packing fraction, moving ordered domains of nearly vertical rods spontaneously form and coexist with horizontal rods. The domains of vertical rods coarsen in time to form large vortices. We investigate the conditions under which the vortices occur by varying the number of rods, vibration amplitude and frequency. The size of the vortices increases with the number of rods. We characterize the growth of the ordered domains by measuring the area fraction of the ordered regions as a function of time. A {\em void filling} model is presented to describe the nucleation and growth of the vertical domains. We track the ends of the vertical rods and obtain the velocity fields of the vortices. The rotation speed of the rods is observed to depend on the vibration velocity of the container and on the packing. To investigate the impact of the direction of driving on the observed phenomena, we performed experiments with the container vibrated horizontally. Although vertical domains form, vortices are not observed. We therefore argue that the motion is generated due to the interaction of the inclination of the rods with the bottom of a vertically vibrated container. We also perform simple experiments with a single row of rods in an annulus. These experiments directly demonstrate that the rod motion is generated when the rods are inclined from the vertical, and is always in the direction of the inclination.Comment: 6 pages, 10 figure, 2 movies at http://physics.clarku.edu/vortex uses revtex

Hard-core Yukawa model for two-dimensional charge stabilized colloids

The hyper-netted chain (HNC) and Percus-Yevick (PY) approximations are used to study the phase diagram of a simple hard-core Yukawa model of charge-stabilized colloidal particles in a two-dimensional system. We calculate the static structure factor and the pair distribution function over a wide range of parameters. Using the statics correlation functions we present an estimate for the liquid-solid phase diagram for the wide range of the parameters.Comment: 7 pages, 9figure